The construction of a layered heterojunction photocatalyst could profoundly promote the charge carrier separation and thus boost the photocatalytic activity. In this work, a two-step exfoliation–reassembly process was first employed to prepare H⁺-restacked H⁺TiNbO₅⁻ nanosheets (HTN), which were then coupled with BiOCl to fabricate layered BiOCl/H⁺TiNbO₅⁻ (BTN) heterojunctions by a hydrothermal method. The photocatalytic performance of the as-prepared samples was evaluated by degrading rhodamine B (RhB) molecules under visible-light irradiation. Among BTN-X (X = 1, 3, 5 and 7) samples with different loading amounts of BiOCl, the BTN-3 sample showed the highest photodegradation efficiency (k = 0.0728 min⁻¹) and excellent photostability. The improved photocatalytic activity was mainly due to the efficient charge carrier separation and transfer resulting from the layered heterostructure. The increased specific surface area and porous structure of BTN-3 could offer more active sites, which was beneficial for facilitating photocatalytic activity. The photoluminescence (PL) spectra and photo-electrochemical analysis confirmed that the formation of a layered heterojunction could shorten the charge migration distance and enlarge the contact area between BiOCl and HTN, leading to efficient separation and transfer of photoinduced charge carriers. Based on the results of active species trapping experiment and ESR spectra, the active species ˙O₂⁻ and h⁺ played a crucial role in degrading RhB molecules under visible light over BTN composites. A possible photocatalytic mechanism was proposed based on the experimental results. This work may provide an insight into the construction of layered heterostructured photocatalysts with high efficiency.

中文翻译：

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用于促进可见光驱动光催化 RhB 降解的分层 BiOCl/H+TiNbO5− 异质结

层状异质结光催化剂的构建可以极大地促进电荷载流子的分离，从而提高光催化活性。在这项工作中，首先采用两步剥离-重新组装工艺制备 H ⁺ -重新堆叠的 H ⁺ TiNbO ₅ ^-纳米片（HTN），然后将其与 BiOCl 偶联以制备层状 BiOCl/H ⁺ TiNbO ₅ ^-（BTN）水热法制备异质结。通过在可见光照射下降解罗丹明 B (RhB) 分子来评估所制备样品的光催化性能。BTN- X ( X= 1, 3, 5 和 7) 不同负载量的 BiOCl 样品，BTN-3 样品显示出最高的光降解效率 ( k = 0.0728 min ^-1) 和出色的光稳定性。光催化活性的提高主要是由于层状异质结构导致有效的电荷载流子分离和转移。BTN-3增加的比表面积和多孔结构可以提供更多的活性位点，有利于促进光催化活性。光致发光 (PL) 光谱和光电化学分析证实，层状异质结的形成可以缩短电荷迁移距离并扩大 BiOCl 和 HTN 之间的接触面积，从而实现光生电荷载流子的有效分离和转移。根据活性物种捕获实验和 ESR 谱的结果，活性物种 ˙O ₂ ^-和 h ⁺在可见光下在 BTN 复合材料上降解 RhB 分子方面发挥了至关重要的作用。根据实验结果提出了一种可能的光催化机理。这项工作可以为构建高效的层状异质结构光催化剂提供见解。